1. Field
The present disclosure relates generally to reducing contaminants in an optically translucent liquid, and more specifically to using a scavenger material to reduce contaminants in a liquid-filled light-emitting diode (LED) bulb.
2. Description of the Related Art
Traditionally, lighting has been generated using fluorescent and incandescent light bulbs. While both types of light bulbs have been reliably used, each suffers from certain drawbacks. For instance, incandescent bulbs tend to be inefficient, using only 2-3% of their power to produce light, while the remaining 97-98% of their power is lost as heat. Fluorescent bulbs, while more efficient than incandescent bulbs, do not produce the same warm light as that generated by incandescent bulbs. Additionally, there are health and environmental concerns regarding the mercury contained in fluorescent bulbs.
Thus, an alternative light source is desired. One such alternative is a bulb utilizing an LED. An LED comprises a semiconductor junction that emits light due to an electrical current flowing through the junction. Compared to a traditional incandescent bulb, an LED bulb is capable of producing more light using the same amount of power. Additionally, the operational life of an LED bulb is orders of magnitude longer than that of an incandescent bulb, for example, 10,000-100,000 hours as opposed to 1,000-2,000 hours.
While there are many advantages to using an LED bulb rather than an incandescent or fluorescent bulb, LEDs have a number of drawbacks that have prevented them from being as widely adopted as incandescent and fluorescent replacements. One drawback is that an LED, being a semiconductor, generally cannot be allowed to get hotter than approximately 120° C. As an example, A-type LED bulbs have been limited to very low power (i.e., less than approximately 8 W), producing insufficient illumination for incandescent or fluorescent replacements.
One approach to alleviating the heat problem of LED bulbs is to fill an LED bulb with a thermally-conductive liquid, to transfer heat from the LEDs to the bulb's shell. The heat may then be transferred from the shell out into the air surrounding the bulb.
However, in some circumstances, the thermally-conductive liquid may become contaminated with organics and/or other material. Contaminating organics may be the result of volatile organic compounds (VOCs) that have been emitted from bulb components and became trapped in the thermally-conductive liquid. Other contaminating materials may be soluble or insoluble depending on the temperature and concentration. For example, soluble contaminants may form due to prolonged exposure to certain elastomers, such as Viton. Insoluble or particulate contaminants may form when soluble contaminants cool and solidify in the thermally-conductive liquid. Particulate contaminants due to the presence of elastomers are also referred to herein as elastomer precipitate.
Over time, organic and other contaminants may discolor optical materials in the LED bulb and degrade the quality of light produced by the LED bulb. The contaminants may also interfere with the operation of the LEDs and cause premature failure of the LED bulb. Thus, a method and system for reducing contaminants in a liquid-filled LED bulb is desired.